If thinking won’t cut it, how does anyone know for assurance that they are saved? Lacking that knowledge, the only assurance at some point is knowing that one is lost.
Excellent question. The answer lies in the New Covenant. I will write My Laws in your heart. IOW, you will obey God’s Laws because you love God and want to please Him. The Law condemns us and cannot save us, only faith on our part and God’s mercy on His part does that. But if you obey His Commandments willingly, you are saved. The unsaved cannot and will hate those that can/do (even Christians).